In machine tools in which large amounts of particulate material is produced by the cutting action of a tool such as a router, drill, grinder or sander, it is required for safety and environmental reasons to remove such material from the work area. In the prior art, it typically has been the practice to remove such material by the use of a hood member mounted on the tool head assembly, encompassing the cutting tool, and a vacuum system for withdrawing the material from the interior of the hood member. Generally, such hood members have been provided with a brush disposed around the periphery of the hood member which engages the workpiece and work table to contain and accumulate the particulate material produced by the cutting tool for removal by the vacuum system. An improvement to such an arrangement is disclosed in copending patent application Ser. No. 08/274,381, now U.S. Pat. No. 5,632,579, incorporated herein by reference, in which the hood member has a lower edge that is spaced from the workpiece when the device is in its operative position, providing a peripheral air inlet opening that increases flow through the exhaust opening and enhances material removal.
A drawback to such systems, however, is that the hood member obstructs the operator's view of the tool bit and the cut made thereby. Even in instances where the hood member is constructed with clear panels, such panels tend to become covered with dust or cutting fluid and are very difficult to keep clean. In metal cutting machines, a hood may not be provided but instead the entire device may be surrounded by an enclosure. In such systems it is still advantageous to provide a facility for remote observation of the cutting operation.